Electric welding.



R. MACK.

ELECTRIC WELDING.

APPLICATION FILED FEB. 29.

Patented June 15, 1915.

WIT NESSES A ITOBIVEYS UNITED STATES PATENT OFFICE.

RICHARD MACK, OF BERLIN, GERMANY, ASSIGNOR TO THOMSON ELECTRIC WELDING COMPANY, OF LYNN, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

ELECTRIC WELDING.

Specification of Letters Patent. Patented June 15 1915 Application filed February 29, 1912. Serial No. 880,731.

h To all whom it may concern metal,

The main object of the invention is to simplify and quicken the process of electrically welding seams in sheet metal such as tubes, cylinders and other forms. I

Another object of the invention is to sim plify the operation of an electric welding apparatus adapted to weld seams whereby there will be a fewer number of parts required and therefore the cost of construction willbe greatly reduced and the relia- 7 bility of operation increased.

I-Ieretofore in the electric welding of seams in tubes, cylinders and other objects of sheet metal it has been the practice to either point-weld the seam, that is weld it at a spot at a time, or to weld it by means of a continuous roller electrode. In either case, the object to be welded had to be carried past the electrodes by hand or automatically or. else the electrode had to be %assed over or along the seam to be welded.

oth of these modes of operation led to many difiiculties in construction, loss of time and consumption of electric power.

In accordance with this invention, which 3 may be designated as a continuous pointwelding operation, the above difiiculties and objections are overcome as the object to be welded remains, during the entire process of welding, in a previously determined fixed position and the electrodes move only in a direction perpendicularto the welding seam. The invention consists in the improved process of and apparatus for the electric welding of seams in sheet metal ware hereafter-more particularly described and then specified in the claims.

The drawings illustrate two ways in which an apparatus or machine constructed in accordance with this invention works in carrying out the improved process.

Figure 1 is a d'agrammatic view of an apparatus with WhlCh this invention may be carriedinto' eflect. Fig. 2 is a diagrammatic view of a portion of the apparatus shown in Fig. 1 and modified to cause the electrodes to be brought into operation in a slightly different manner.

Referring to the drawings a indicates the main frame of the machine and upon which the parts are mounted. The transformer or transformers for supplying electric energy to heat the work is or are of the usual wellknown type and may be of any desired number coupled together in a manner now well known in the art, the apparatus illustrated being" provided with but a single transformerf.

Bars 5 and it projecting laterally from the framework a and preferably parallel with each other form the terminals of the transformer, one being connected to each pole of the transformer secondary and furnishing cur rent to the work engaging contacts or electrodes carried thereby in a well known manner. The arms 5 and It may be of any desired length v according to the length or size of the object or material to be welded and are suitably insulated from each other and from the frame of the machine.

The lower arm b is preferably provided with a plurality of work engaging electrodes or contacts preferably in the form of pins 0 located in side contact with each other although if desired the lower electrode 0 might be formed as a continuous strip. The arm I; and electrodes 0 form a support upon which the work, as for 1nstance a tube or cylinder g, is suitably clamped or held.

c indicateselectrodes which move vertically in The electrodes 0 lie opposite and are equal in number to the electrodes or contacts 0 on the lower arm I). The electrodes 0' lie in side contact with each other or in such close proximity that the weld caused by any one of them will overlap'that of 1ts neighbor to form a substantially continuous scam in the work g, located between the extremities of a slot in the arm 71., from which they receive electric-current from the transformer ing supported by an arm a? and the shaft rotated by power applied in any desired manner.

The operation is as follows :The tube or sheet to be welded is placed with the portions to be welded on the contacts 0 of the lower electrode arm I), the current is turned on and the machine is set in motion. The shaft (2 with its cams works the eccentrics M in such a manner that the point electrodes 0' successively make a point weld. Owing to the regularity and close arrangement of the electrodes, an approximately continuous seam weld results.

It will be understood that the making and breaking of the circuit may be controlled in any desired way either by hand or automatically under the control of the movable electrodes or work in synchronism with the movement of the electrodes, as this part of the operation is well known in the art. Also it will be understood that the manner of supplying current to the bars I) and k is for the purpose of illustration only and that more than 'one transformer may be employed and the arrangement may be varied without departing from the spirit of the invention as set forth in the appended claims.

Referring to Fig. 2 the upper movableelectrodes, instead of being arranged to be operated in succession throughout the length of the seam to be welded, are arranged in two groups, 0 and 0 and the eccentrics M on the shaft 6 are so disposed as to actuate the first electrodes of each group simultaneously, the second electrode of each group simultaneously and so on throughout the length of the seam. By this arrangement the speed of the welding operation is increased, the arrangement of the'circuit remaining as in the case previously described. Obviously the electrodes may be arranged in any desired number of groups, the electrodes of each group being brought into op eration successively.

The invention claimed is 1. The process of electric welding consisting in arranging the work between a plurality of groups of spot welding electrodes, each group comprising a multiplicity of electrodes arranged in side contact with each other, actuating said electrodes of each group in succession and passing an electric current from one to the other through the work whereby an approximately continuous seam weld is attained.

2. The process of continuous seam welding consisting in locating the work between a multiplicity of pairs of permanently located point electrodes arranged in side contact, maintaining the work stationary during the entire seam welding operation, act-uating each pair of electrodes in succession to trodes in succession and in inaaaao successively engage different parts of the work, passing an electric current from one electrode of each pair to the other and applying pressure whereby an approximately continuous weld is attained.

3. In an electric welding apparatus, the combination of a plurality of pairs of spot welding electrodes arranged in side contact with each other, means for actuating said electrodes in succession to grip the work between them and means for passing an electric current from one to the other of each pair of electrodes whereby an approximately continuous seam weld is attained.

4c. lln an electric seam welding apparatus, the combination of a transformer having a terminal for engaging one side of the work to be welded, a plurality of electrodes arranged in side contact and adapted to engage the opposite side of the work and means for actuating said electrodes in succession to effect a continuous seam weld.

5. lln an electric seam welding apparatus, the combination of a transformer, bars secured to the terminals of said transformer,

one of said bars provided with contacting surfaces for engaging one side of the work to be welded, a plurality of separate movable electrodes arranged in side contact with each other and connected to the other of said bars and means for actuating said elecpredetermined order.

6. In an electric seam welding apparatus wherein the work remains stationary, a transformer, a bar connected to one terminal thereof and provided with stationary work contacting surfaces, a bar connected to the other terminal of said transformeiya plurality of separate, movable electrodes arranged in side contact and passing through said second named bar and means adapted to actuate said electrodes to successively engage parts of the work located between the two said bars.

7 In an electric seam welding apparatus, the combination of a transformer, a pair of parallelbars, one connected to each term nal of said transformer, a plurality of stationary work engaging contacts secured to one of said bars, a plurality of movable, pinshaped electrodes passing through the other bar and arranged in side contact with each other and means adapted to successively actuate said electrodes to engage the work opposite said stationary contacts.

In testimony whereof I have affixed my signature in presence of two witnesses.

RICHARD MACK.

Witnesses JULIUs RUMLAND, KARL RIEKEBEN. 

